Can,

Take a look at the newValuesStream, maybe you can chain another aggregator
on top of your first persistentAggregate this way.

On Tuesday, June 24, 2014, Can Gencer <[email protected]> wrote:

> This would probably work, however it wouldn't be reusing the calculations
> already done after the group by, which was my main intention.
>
>
> On Tue, Jun 24, 2014 at 6:15 PM, Adam Lewis <[email protected]
> <javascript:_e(%7B%7D,'cvml','[email protected]');>> wrote:
>
>> It sounds like you want a persistentAggregate to occur before the stream
>> grouping by word, would this work?
>>  in pseudo trident DSL:
>>
>> Stream words = ...;
>> words.groupBy(word).persistentAggregate(...);
>> words.persistentAggregate(...);
>>
>>
>> On Tue, Jun 24, 2014 at 12:45 PM, Can Gencer <[email protected]
>> <javascript:_e(%7B%7D,'cvml','[email protected]');>> wrote:
>>
>>> Hi all,
>>>
>>> I'm wondering what is the best way to "chain" persistent aggregations in
>>> Trident.
>>>
>>> Let's say I have a running count of words and I also want to do another
>>> aggregation to calculate the total count of all words using the results of
>>> the previous aggregation.
>>>
>>> I can use a persistentAggregate to calculate the running total for each
>>> word. However I can't use another persistentAggregate directly chained to
>>> that as that would only add the new value instead of decrementing the old
>>> value for the group first.
>>>
>>> What is the best solution to this scenario? Does storm have a way to
>>> handle this out of the box?
>>>
>>> Regards,
>>> Can
>>>
>>
>>
>

-- 
Danijel Schiavuzzi

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